The following co-pending applications on machining subject matter are herein incorporated by reference:
A. Apparatus For Determining Dimensions, U.S. Ser. No. 08/124,605, filed Sep. 21, 1993, now U.S. Pat. No. 5,362,970.
B. Controlled Machining, U.S. Ser. No. 07/509,295, now U.S. Pat. No. 5,112,131.
C. Control of Lathes, U.S. Ser. No. 07/884,331, filed May 18, 1992, now abandoned.
D. Lathes PCT/US93/04857, filed May 17, 1993.
E. Contact CIP U.S. Ser. No. 08/071,012, filed Jun. 2, 1993, now U.S. Pat. No. 5,871,391.
The following co-pending applications on sensing or assembly related subject matter herein incorporated by reference:
1. Method And Apparatus For Assembly Of Car Bodies And Other 3 Dimensional Objects, PCT Appl. PCT/CA92/00296, filed Jul. 30, 1992.
2. Method and Apparatus for Assembly, U.S. Ser. No. 07/728,682, filed Jul. 12, 1991, now U.S. Pat. No. 5,380,978.
3. Robot Vision Using Targets, U.S. Ser. No. 07/664,574, filed Mar. 6, 1991, now U.S. Pat. No. 5,506,682 (also U.S. Pat. No. 4,654,949).
4. Target Based Determination Of Robot And Sensor Alignment, U.S. Ser. No. 07/733,035, filed Jul. 22, 1991, now abandoned (also U.S. Pat. No. 4,796,200).
5. Vision Assisted Fixture Construction, U.S. Ser. No. 07/866,653, filed Apr. 8, 1992, now U.S. Pat. No. 5,267,143.
6. Robot Vision Using Holes, Corners, Etc. U.S. Ser. No. 07/697,345, filed May 9, 1991, now abandoned.
7. Improvements in Assembly Tooling, U.S. Ser. No. 08/002,384, filed Jan. 11, 1993, now abandoned.
8. Car Body Assembly, U.S. Ser. No. 07/728,682, filed Jul. 12, 1991, now U.S. Pat. No. 5,380,978.
1. U.S. Pat. No. 4,373,804xe2x80x94Method And Apparatus For Electro-Optically Determining The Dimension, Location And Attitude Of Objects
2. U.S. Pat. No. 4,394,683xe2x80x94New photodetector array based optical measurement systems
3. U.S. Pat. No. 4,453,085xe2x80x94Electro-Optical Systems For Control Of Robots, Manipulator Arms And Coordinate Measurement Machines.
4. U.S. Pat. No. 4,667,231xe2x80x94Electro Optical Part Inspection In The Presence Of Contamination, And Surface Finish Variation.
5. U.S. Pat. No. 4,774,751xe2x80x94Electro Optical And Robotic Casting Quality Assurance
6. U.S. Pat. No. 4,576,482xe2x80x94Electro-Optical Inspection
7. U.S. Pat. No. 4,403,860xe2x80x94Apparatus For Determining Dimensions
8. U.S. Pat. No. 4,574,199xe2x80x94Sensing location Of An Object
9. U.S. Pat. No. 4,585,350xe2x80x94Pulsed Robotic Inspection
10. U.S. Pat. No. 4,559,684xe2x80x94Controlled Machining Of Combustion Chambers, Gears, And Other Surfaces
1. U.S. Pat. No. 5,010,634xe2x80x94Vehicle Assembly Method And Apparatus, assigned to Nissan Motor Co.
The thrust of manufacturing in the decades to come will be toward continuing reductions in cost, improvements in quality, and most dramatically for changes in manufacturing methods as a vastly increased flexibility of manufacture to respond immediately to market trends occurs. Such flexibility has been the hallmark of the success of companies in the clothing business, for example, and is now being advocated for all types of business including those in the traditional hard goods sector. A Term, xe2x80x9cAgile Manufacturingxe2x80x9d has been coined to describe this new paradigm.
The provision of manufacturing systems however that can deliver agile performance while maintaining the lowest cost and highest quality is extremely difficult. In years past, these three goals each has been viewed as mutually exclusive with the others. For example, in order to reduce cost, the famous Ford assembly line eliminated flexibility to market change, creating one style and producing it for a long period of time, with at least reasonable quality. Recently the Japanese, for example in the car business, have begun to hone the traditional processes of car manufacture to a fine degree raising the level of quality well beyond its previous state, but still with very little flexibility. Other cars, such as certain exotic marquees made in much smaller quantities, achieve quality and flexibility, but at high cost. Even with these however, flexibility is still not achieved until such extremely small volumes are reached that the car becomes virtually hand made.
This being the case then, how can mass market items produced rapidly to a market change in ever smaller economic lots at lowest cost be affordable and still maintain the highest quality? It seems virtually impossible, and yet this is the goal that has been set out by both Japanese and American studies for achievement in the 21st century.
If this isn""t enough, further thrusts toward improved performance, both environmentally and functionally, are requiredxe2x80x94in the car business, for example, this means improved acceleration, fuel economy, etc. In order to achieve improved performance, much higher accuracies are being required in the production of key critical components.
The accuracy requirements are not simply limited to the powertrain or functional components, but are also related as well to almost all other parts, such as anti-skid brake systems and even the sheet metal body. For the sheet metal body, where a relentless quality push has taken place in North America, at some point this push approaches the law of diminishing returns (since the benefits are increasingly subjective as opposed to functional).
Before proceeding to the technical aspects of the invention, there are other trends in the manufacturing technology world today. Some of these have been pinpointed in the Lehigh Study, and other recent attempts to formulate industrial policy in the United States. The area that this application and my previous work is most concerned with, is intelligent sensors, machine intelligence, and knowledge based systems. These form the building blocks on which the flexible machines and automation that can achieve the goals above in an accurate low cost manner can be built. They are also in an area that is very difficult to do, and to some degree only now begins to become possible economically due to the drastically lowering cost of the computation facilities, and the maturing of key sensor technologies, particularly electro-optics/machine vision, which would allow them to be used reliably in plant applications.
There are other trends, such as the move toward openness in the controls areas, which allows the sensory data to be imputed in a manner suitable for action on the plant floor, but without being locked up by proprietary systems. There is also obviously an ever present trend toward lower computer costs, which can be extrapolated on to produce, along with lower memory costs, a massive increase in the ability to use xe2x80x9cknowledge and intelligencexe2x80x9d to deal with the ever present problems on the plant floor. While the computation and memory costs are changing rapidly, sensing technologies, however, are not. It can be assumed that those in place today will, in xe2x80x9cever betterxe2x80x9d but not drastically changed form, provide the basis for the manufacturing systems of the year 2000 onward.
The trend toward knowledge and intelligence is manifested in the ever increasing role of software, and the operation of reliable software in these machines is critical. Also critical is that the sensory data provided, which yields the basis on which intelligence can be done, is correct.
This leads to the next issue, the selection of sensors. Here, it is my thesis that just as in the factory of today, the principal sensor is the worker""s eye, so it is here that some sort of electro-optically based sensor, whether it approximates human vision or not, is indeed key. There are many reasons for this, among them non-contact operation, freedom from wear, large stand-off, accuracy, multi-varied task ability, etc. I have found in the course of working in this field for the last 20 years that most all variables that need to be sensed in the manufacture of hard goods can be indeed sensed electro-optically, and generally best with image based sensors of some kind. In some cases, they may be better sensed by other means, such as contact gages or the like, but in general the electro-optical solution is the one with the most application, and which most approximates the human.
The key though is to do what the human can do flexibly, but to also achieve the precision and the freedom from fatigue that machines can provide. The key sensor for this purpose, that can guide machines in a human like manner but with the accuracy of the machine, is electro-opticalxe2x80x94and generally image basedxe2x80x94just like the human eye.
The Importance of the speed of measurementxe2x80x94without crashes
A key issue that many have not have realized is the importance of the speed of measurement to intelligent process control. While one can have a workable measurement of, let us say, the part diameter with contact probes that could operate within a machine tool, the actual use of such contact probes is very limited. The slowness of their operation and their propensity for xe2x80x9ccrashesxe2x80x9d has limited their application, particularly in high production applications where the advantages of such intelligent control built up of a number of small improvements in every sector have not heretofore been fully realized. Non contact, brig standoff, crash free operation suitable for in process, in machine, operation is thus very important.
The Importance of the synergistic sum of small improvements
The summation of a number of small improvements can create overall a large difference between use of the intelligent machines and systems, and conventional ones. For example, implementation of intelligent control of turning operations alone in one large automaker""s production is estimated to save $200,000,000 per year if implemented across the boardxe2x80x94even though each individual feature itself, such as longer tool life might only save a small fraction of this number. There is an economy of scale of sensing and intelligence.
We also have to look at the issues that surround the ability of the machine to make parts that are better on a statistical variability basis, by a large measure, even though the machine itself, on the day of its manufacture, is perhaps hardly better than a regular machine of the same type. This has very important ramifications for the xe2x80x9csafetyxe2x80x9d factors that are used in modern day design of manufactured parts.
Intelligence Versus Adaptive Control
Machine intelligence is often considered to be adaptive control; that is taking the immediate inputs from the process, such as forces, vibration, etc., and feeding them back to control the machine. Such efforts go back to the xe2x80x9850xe2x80x99s, as evidenced by the prior art cited in co-pending applications C and D noted above.
Historically, such adaptive control has largely concerned itself with the machine""s physical variables and their input to control the machine, using these variables, such as tool force, for example, to infer the proper maintenance of cutting conditions in machine tools. Heretofore, there has been, by comparison, relatively little emphasis on any relationships of the part variables such as dimension or finish, or in the interplay between tool and part variables also in related processes. The tool was assumed perfect, and the machine assumed to go to the position desiredxe2x80x94neither of which is true in practice at the accuracy levels required for modern parts manufacture.
This invention is related to numerous others of my inventions, listed in the references above, and continues in part the ideas represented therein.
The invention seeks to illustrate that the modern sensing capabilities, particularly, but not necessarily those provided by electro-optical sensors, can provide the creation of data within a manufacturing system that can be used for the intelligent control of the process, both of the instant work element such as a machine tool or welding tool, and of the process elements in the factory that connect with it.
The goal of this invention is to demonstrate the intelligent control of manufacturing processes, and in particular machining and fabricated parts assembly.
It is a goal of this invention to disclose a method for automatic development of processes within a machine, or a cell containing a group of similar machines, or a process including a number of inter-connected operations, including a machine.
It is also a goal of the invention to illustrate means for controlling the removal, or addition, of material to objects.
It is also a goal of the invention to provide a means for automatically programming machine tools from master parts.
It is a goal of the invention to provide a common operator display for machines, such as a machine tool, which can provide CCTV based video data presentation of actual images from within the process, as well as from sensed data concerning the tools or parts, and from training and other diagnostic presentations of the operation of the machine.
It is also a goal of the invention to control movements of hydraulic, or other micro-positioning devices and assembly tools to change the location of the positioning points to improve the product produced.
It is also a goal of the invention to provide sensing devices for surface and hole location built within the press dies, as well as in assembly tools.
It is also a goal of the invention to establish data bases, which can not only be accessed concerning parts and tools used within a machine, but which can also be accessed and transmitted to other processes connected to a machine for control thereof.
It is also a goal of the invention to illustrate the interactive control of operations using high speed optical sensing, such as provided electro-optically, to gather sufficient data on production parts that intelligent decisions, both for that machine and for other inter-connected processes and machines, can be made.
It is a goal of the invention to illustrate means for controlling the casting and heat treating processes providing parts to machine tools.
It is a goal of the invention to provide novel means for improving the accuracy of turned surfaces worked in a machine tool.
It is a goal of the invention to account for the deformation of materials under working, and for unpredictable deformations due to complex, external and internal part geometries, and in complex fabricated assemblies.
It is a goal of the invention to provide for means and novel methods for obviating the deleterious effects of contamination on electro-optical sensor windows used in production machines.
It is a goal of the invention to acquire and utilize intensive part or tool surface data to provide a best fit of surfaces, and to better predict the need for contour machining or other finishing processes on parts, and for the assembly into other parts.
It is the goal of the invention to describe a system for assembling car bodies and other equipment combining a reconfigurable fixed tooling, as well as robotically positionable and programmable part location.
It is a goal of the invention to disclose means for using a machine to learn the characteristics of parts produced within it, and parts presented to it, as well as to learn the correct settings of sensor units used therefore of master parts of the types used.
It is a further goal of the invention to illustrate new forms of checking fixtures for sheet body metal components which can be used easily within coordinate measuring machines, as well as for rapid data taking on the plant floor, including fixtures that can be reconfigured for other applications or new models.
It is a goal to show how cost of production can be reduced in all its aspects by considering the use of intelligence systems to optimize all processes linked together to produce a given part (plastics, stamping, fasteners, machining, casting, etc.)